What are the warning signs of dehydration on a job site?

Derek was pouring a foundation in Mesa. 108 degrees. Thought he felt fine.

Then his foreman noticed he’d stopped talking. Just stood there, trowel in hand, staring at the concrete.

“Hey. Derek.”

Nothing.

They got him to shade. Got water in him. He came back around. Didn’t remember the last hour.

That’s how fast it happens.

The progression nobody talks about

Dehydration isn’t binary. You’re not fine and then suddenly not fine. It’s a gradient, and the early signs are easy to miss if you don’t know what you’re looking for.

Here’s what happens, in order:

Stage 1: Mild dehydration (1-2% body weight lost)

You probably won’t notice. Maybe a slight headache. Maybe your mouth feels dry. Your urine is darker than usual.

The tricky part: Thirst kicks in here. But thirst is a lagging indicator. By the time you’re thirsty, you’re already behind.

Stage 2: Moderate dehydration (3-5% body weight lost)

Now you’re in trouble. Symptoms:

• Dry mouth, no sweat even though you’re hot
• Dark urine (amber to brown)
• Muscle cramping
• Fatigue that hits like a wall
• Headache that won’t quit
• Dizzy when you stand up fast

This is where Derek was. Functional, technically. But not making good decisions.

Stage 3: Severe dehydration (6%+ body weight lost)

Hospital territory:

• Confusion, irritability
• Rapid heartbeat, rapid breathing
• Sunken eyes, shriveled skin
• No urine for hours
• Fainting or seizure

This is heat stroke territory. Call 911. Don’t wait.

The early warning system

The problem is that dehydration messes with your judgment. The more dehydrated you get, the worse your decisions become. It’s like being drunk—you don’t realize you’re impaired.

Here’s what to watch for in yourself and your crew:

The stop-talking sign. Someone who was chatty goes quiet? Red flag.

The thousand-yard stare. Focused on nothing? Not a good sign.

The coordination drop. Dropping tools, stumbling, movements getting sloppy?

The “I’m fine” response. Dehydrated people always say they’re fine. Ask how they’re feeling. A vague or confused answer is worse than an honest complaint.

The prevention

Weigh yourself. Seriously. Before and after a shift. If you’ve lost more than 2% of body weight, your hydration strategy is failing.

Set a timer. Every 20 minutes, drink. Don’t wait for thirst.

Electrolytes matter. Plain water isn’t enough for heavy sweating. Add electrolyte powder or alternate with sports drinks. Companies like Built Daily Supply make hydration products designed for guys losing liters of sweat per hour.

Buddy system. Watch your partner. Make them watch you. Dehydrated people make bad decisions about their own dehydration.

The bottom line

Derek got lucky. His foreman was paying attention.

Not everyone has that. Know the signs. Watch your crew. The life you save might be your own.